Add @Native(...) annotation for native class names.

tests/compiler/dart2js_native/browser_compat_1_prepatched_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import "dart:_js_helper";
 import "package:expect/expect.dart";
 //import 'dart:_foreign_helper' show JS;
 //import 'dart:_js_helper' show Creates, setNativeSubclassDispatchRecord;
 
 // Test for dartNativeDispatchHooksTransformer, getTag hook.
 
-class T1A native "T1A" {
+@Native("T1A")
+class T1A {
 }
 
-class T1B native "T1B" {
+@Native("T1B")
+class T1B {
 }
 
-class T1C native "T1C" {
+@Native("T1C")
+class T1C {
 }
 
 makeT1A() native;
 makeT1B() native;
 makeT1C() native;
 
 int getTagCallCount() native;
 
 void setup() native r'''
 function T1A() { }       // Normal native class.
@@ skipping 55 matching lines @@
   Expect.equals(true, t1c is T1C, '$t1c is T1C');
 
   Expect.equals(2, getTagCallCount());
 
   Expect.equals(true, inscrutable(t1a) is T1A, '$t1a is T1A');
   Expect.equals(true, inscrutable(t1b) is T1B, '$t1b is T1B');
   Expect.equals(true, inscrutable(t1c) is T1C, '$t1c is T1C');
 
   Expect.equals(2, getTagCallCount());
 }